A. To determine whether chronic endurance training is protective against silent myocardial ischemia (SI), we determined the prevalence of exercise-induced SI ST segment depression on exercise ECG and segmental perfusion defects on tomographic (SPECT) thallium scan) in 70 male master athletes aged 63 plus minus 6 yrs and 85 healthy, age-matched untrained men.The prevalence of SI was similar in athletes and untrained men (16% vs 21%, p=0.36). Of note, the apolipoprotein E4 phenotype was present in 9 of the 11 athletes with SI compared to only 2 of 32 athletes with normal exercise results (p less than or equal to 0.001). B. Whether exercise tomographic (TOMO) thallium (TI) imaging improves the detection of future coronary events (CE) compared with planar Tl imaging in apparently healthy volunteers is not known.Accordingly, the sensitivity, specificity and predictive value of Tl was assessed in 329 BLSA volunteers 40-87 years old and compared with planar Tl results in another 407 similar BLSA subjects.The prevalence of silent ischemia (SI), defined by concordant ST segment changes and a planar or TOMO Tl defect, increased approximately 7-fold from the fifth to the eighth decades. Although the sensitivity and specificity of planar Tl (28% and 97% respectively) were nearly identical to those for TOMO Tl (28% and 89%, respectively), for identifying future CE, the positive predictive value for planar Tl (48%) was significantly higher than that for TOMO Tl (17%).C.To determine whether ischemic ST segment changes occurring only during recovery from maximal treadmill exercise predict future coronary events (CE) in clinically healthy populations, we compared 2 groups of BLSA subjects: 150 with 1mm ST segment depression occurring during exercise (Group 1) and 64 with such ST changes limited only to recovery (Group 2). The 2 groups were similar in age, gender, and coronary risk factors.Over a mean follow-up of 7.3 years, CE (angina pectoris, myocardial infarction or coronary death) developed in 14.6% of Group 1 and 18.7% of Group 2, p=NS.By logistic regression analyses older age (p=.0007), higher serum cholesterol (p=.002) and shorter exercise duration (p=.002) but not the time of ST depression onset(exercise vs recovery) were independent predictors of future CE.